make expected-tests diff more pretty (#2577)

* make expected-tests diff more pretty

* use owo-colors, which is more pleasant

Author: tshepang

Cargo.lock

@@ -8,11 +8,12 @@ publish = false
 bindgen = { path = "../bindgen", features = ["__cli", "experimental"] }
 clap = { version = "4", features = ["derive"] }
 clap_complete = "4"
-diff = "0.1"
 shlex = "1"
 prettyplease = { version = "0.2.7", features = ["verbatim"] }
 syn = { version = "2.0" }
 tempfile = "3"
+similar = { version = "2.2.1", features = ["inline"] }
+owo-colors = "3.5.0"
 
 [features]
 logging = ["bindgen/logging"]